Technical Field
The present invention relates to a power supply system that includes multiple local systems, each of which has an AC line to which multiple power consumers are connected, a power storage device, and a local inverter device that connects the power storage device and the AC line, and in this power supply system, a linking inverter device for linking the power storage device of one local system to the AC line of another local system is provided between the local systems such that the local systems are electrically connected in series.
Background Art
A power supply system that has been proposed in the past includes multiple local systems that each have an AC line to which multiple power consumers are connected, a power storage device, and a local inverter device that connects the power storage device and the AC line. For example, in the power supply system described in Patent Document 1 (WO 2010/103650), a linking inverter device for linking the power storage device of one local system to the AC line of another local system is provided between the local systems such that the local systems are electrically connected in series. Furthermore, the local inverter devices of the respective local systems are caused to operate such that the voltage of the power on the AC line is at a target voltage, and such that the frequency of the power on the AC line is at a target frequency determined according to the state of charge of the power storage device. Also, with respect to two local systems that are electrically connected via one linking inverter device, the operation of the linking inverter device is controlled such that electric power is supplied from the local system having the higher target frequency to the local system having the lower target frequency. In other words, the frequency of the power on the AC line in each local system is a value that reflects the state of charge of the power storage device, and therefore by merely detecting the frequencies of the AC lines of two local systems that are electrically connected, the linking inverter device can find out which local system has the power storage device with the higher state of charge. Power interchange is then performed between the local systems according to the magnitude relationship of the detected frequency values, thus making it possible to equalize the states of charge of the power storage devices in the local systems.
Patent Document 1: WO 2010/103650